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COVID-19 vaccine weekly safety report - 07-10-2021

Vaccination against COVID-19 is the most effective way to reduce deaths and severe illness from infection. Millions of people have now received COVID-19 vaccines under the most intense safety monitoring ever conducted in Australia.

Three COVID-19 vaccines are currently in use in Australia – Vaxzevria (AstraZeneca), Comirnaty (Pfizer) and Spikevax (Moderna). To be registered for use, these vaccines must meet the TGA’s high standards for quality, safety and effectiveness.

Like all medicines, COVID-19 vaccines may have some side effects (also known as adverse events). The overwhelming majority of these side effects are mild and resolve within a few days. More serious side effects can occur after vaccination but are very rare.

The TGA closely monitors reports of suspected side effects to the COVID-19 vaccines and provides regular updates on vaccine safety in this report. Find out how the TGA identifies and responds to a safety concern.

Importantly, suspected adverse events reported to the TGA are often not caused by the vaccines. Learn more about causality and the TGA’s COVID-19 vaccine safety monitoring and reporting activities.

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Summary

  • The protective benefits of vaccination against COVID-19 far outweigh the potential risks of vaccination.

  • To 3 October 2021, approximately 28.8 million vaccine doses have been given in Australia 17 million first doses and 11.8 million second doses.

  • The most frequently reported side effects suspected to be associated with the vaccines reflect what was seen in the clinical trials. They include injection-site reactions such as a sore arm, and more general symptoms such as headache, muscle pain, fever and chills.

  • We are closely monitoring rare reports of blood clots with low blood platelets (also called thrombosis with thrombocytopenia syndrome or TTS) linked to Vaxzevria (AstraZeneca).

  • In the last week, an additional 3 reports of blood clots and low blood platelets have been assessed as confirmed or probable TTS, bringing the total number of cases to 151.

  • We continue to carefully monitor reports of suspected myocarditis and/or pericarditis following the Comirnaty (Pfizer)and Spikevax (Moderna) vaccines, particularly in the younger age groups. 

  • The Spikevax (Moderna) vaccine is now being rolled out in Australia. To 3 October 2021, we have received 65 reports of suspected adverse events.

Reported side effects for COVID-19 vaccines

Gathering reports of adverse events following immunisation (AEFI) is just the first step in determining whether the effect is related to the vaccine and whether a significant safety issue is involved. Learn more about how the TGA identifies and responds to safety issues.

In the general population (16 years of age and over), the most frequently reported side effects suspected to be associated with the vaccines include injection-site reactions such as a sore arm, and more general symptoms such as headache, muscle and joint pain, and fever and chills.

Now the vaccines are being rolled out more widely, we are receiving more reports in younger individuals. The TGA is monitoring these reports closely. We know from the Comirnaty (Pfizer) and Spikevax (Moderna) clinical trials that the most common adverse reactions in adolescents are similar to those in older people and include injection-site pain, fatigue and headache. Most of these side effects were mild and resolved within a day or two. For both vaccines, they were more common after the second vaccine dose than the first.

Review of the TGA adverse event database to 3 October 2021 indicates that the most commonly reported reactions in adolescents after vaccination with Comirnaty and Spikevax are dizziness, headache, fainting (syncope), feeling faint (pre-syncope) and nausea. These are expected reactions based on what was seen in the clinical trials. However, at this point they are early observations based on limited data as we continue to closely monitor safety in this age group. 

To help us monitor the safety of the COVID-19 vaccines, we encourage people to report suspected side effects even if it is not certain that the vaccine caused them. Anyone can report a suspected side effect including members of the public, nurses, pharmacists, doctors, health authorities and pharmaceutical companies. A report can be made directly to the TGA, through a health professional, or by calling the NPS MedicineWise Adverse Medicine Events phone line for consumers. Reporting can be anonymous if preferred. For more information click Report a suspected side effect.
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Total adverse event reports to 3 October 2021

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2.3
Reporting rate per 1000 doses
66,829
Total AEFI reports received
28,769,273
Total doses administered
37,774
Total reports for Vaxzevria
28,667
Total reports for Comirnaty
65
Total reports for Spikevax
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To 3 October 2021, the total number of adverse event reports received where the brand of the COVID-19 vaccine was not specified was 369.

Reporting rates per 1000 doses by jurisdiction

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1.6
Australian Capital Territory
1.6
New South Wales
2.2
Northern Territory
2.3
Queensland
2.3
South Australia
4.2
Tasmania
3.2
Victoria
2.3
Western Australia

Reports of death in people who have been vaccinated

Large scale vaccination means that coincidentally some people will experience a new illness or die within a few days or weeks of vaccination.

The TGA reviews all deaths reported in people who have been vaccinated. As the number of vaccinated people has increased, so has reporting of fatal events with a coincidental association with vaccination. This does not indicate a link between vaccination and the fatalities reported. Review of individual reports and patterns of reporting does not suggest the vaccines played a role in these deaths.

Since the beginning of the vaccine rollout to 3 October 2021, over 28.8 million doses of COVID-19 vaccines have been given. So far, the TGA has found 9 reports of death that were linked to immunisation from 585 reports received and reviewed. The overwhelming majority of deaths reported to the TGA following vaccination occurred in people aged 65 years and older. The deaths linked to immunisation occurred after the first dose of Vaxzevria (AstraZeneca) – 8 were TTS cases and one was a case of immune thrombocytopenia (ITP).

Vaxzevria (AstraZeneca) vaccine

To 3 October 2021, approximately 12 million doses of Vaxzevria (AstraZeneca) have been administered in Australia. The reports of suspected side effects we receive for this vaccine are consistent with what has been observed in the clinical trials and by other medicine regulators overseas. Most side effects resolve within a few days.

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Thrombosis with thrombocytopenia syndrome (TTS)

We are closely monitoring rare reports of blood clots with low blood platelets (also called thrombosis with thrombocytopenia syndrome or TTS) linked to Vaxzevria (AstraZeneca).

Early detection of TTS may help to prevent more serious complications developing. Guidance for health professionals is now available which outlines when to suspect TTS, initial tests that can be performed in primary care and when to refer people for emergency care. Patients presenting with low platelets and a headache should be thoroughly investigated for blood clots in the brain, including careful review of imaging results to identify early, small clots. The Royal Australian and New Zealand College of Radiologists have published imaging recommendations for patients with suspected TTS.

People should seek immediate medical attention if they develop any of the following symptoms after vaccination:

  • severe or persistent headache, blurred vision, confusion or seizures

  • shortness of breath, chest pain, leg swelling or persistent abdominal pain

  • unusual skin bruising and/or pinpoint round spots beyond the site of vaccination.

The most common time period for onset of TTS symptoms is 4–30 days after vaccination.

To date, there have been 151 cases of TTS assessed as related to Vaxzevria (AstraZeneca) from approximately 12 million vaccine doses. These cases most often occurred about 2-3 weeks after vaccination. The risk of TTS after a second dose appears to be much lower than after the first dose. Women in younger age groups seem to be slightly more likely to develop clots in unusual locations, such as the brain or abdomen, which have more serious outcomes. Eight people have died as a result of TTS – 6 of these were women. In Australia, the risk of dying from TTS after vaccination is approximately 1 in a million (people receiving a first dose), and somewhat less than this when both doses are taken into consideration.

While TTS is very rare, some people may have concerns that they can discuss with their doctor. ‘Weighing up the potential benefits against risk of harm from COVID-19 Vaccine AstraZeneca’ includes information to help people make informed decisions about vaccination.

Details of TTS cases to date

Since last week’s report, a further 3 reports of blood clots and low blood platelets have been assessed as confirmed or probable TTS likely to be linked to the first dose of Vaxzevria (AstraZeneca). Two of the new cases were in individuals aged under 60 years (Table 1). We continue to closely monitor cases of TTS as Vaxzevria (AstraZeneca) is now being used more frequently in people aged under 60 years. To date, we have not observed a significant change in the rate of TTS in people aged 50-59 years. There has been a trend for the rate to decrease in people under 50-years, but due to the low number of cases this is not statistically significant.

Table 1: Newly confirmed and probable TTS cases for the week of 1-7 October 2021‡ 

New confirmed TTS

New probable TTS

One new case:

  • 82-year-old woman from NSW

Two new cases:

  • 41-year-old man from NSW

  • 52-year-old woman from Queensland

As previously reported, the TGA determines whether a report is likely to represent TTS by assessing cases against accepted criteria established by the UK’s Medicines and Healthcare products Regulatory Agency. 

This takes the total Australian reports assessed as TTS following Vaxzevria (AstraZeneca) to 151 cases (84 confirmed, 67 probable) from approximately 12 million vaccine doses.

To date, 18 cases of TTS have occurred after the second dose. Twelve cases have been classified as probable TTS, with 6 cases meeting the criteria for confirmed TTS. All cases have occurred in individuals older than 50 years, with 15 of the cases in people over 60 years of age. The vast majority of the patients had clots in common locations, such as the lungs or legs, with only 3 cases classified as Tier 1 (see below). The information available to us indicates that only one of these patients required treatment in the intensive care unit, and 15 individuals have been discharged from hospital. Our preliminary analysis is consistent with overseas investigations which have shown that the risk of TTS after the second dose is extremely low. 

When assessed against the criteria used by the US Centers for Disease Control and Prevention (CDC), fewer than half of the cases reported to the TGA are classified as Tier 1 cases which tend to have more serious outcomes. Tier 1 cases involve clots in an unusual location, such as the brain or abdomen (Table 2). Australian data indicates that patients aged under 50 years of age are more likely to be classified as Tier 1 and/or require treatment in intensive care. However, more than one third of these younger patients have not required treatment in intensive care. 

Table 2: Total confirmed and probable TTS cases to date by age and CDC classification

Age

Total cases

Reports per 

100,000 doses‡

CDC classification†

Tier 1

Tier 2

Not classified

<30 years

7

1.8 

(<50 years)

2

3

2

30-39

5

4

1

-

40-49

9

6

1

2

50-59

36

3.0

19

11

6

60-69

35

1.5

11

9

15

70-79

40

2.0

10

12

18

80+

19

1.8

9

6

All ages

151

(75 men,

76 women)

2.0

56

(20 men, 

36 women)

46

(28 men, 

18 women)

49

(27 men, 

22 women)

‡ Rates of TTS are calculated based on first doses of the Vaxzevria (AstraZeneca) vaccine as of 23 September 2021 to account for the time to onset of TTS. These rates are estimates of risk based on small numbers of cases so far. An aggregated rate is given for people aged 18–49 years as the number of cases for each 10-year age bracket is too low to calculate reliable estimates.

† The US CDC classification is defined as:

  • Tier 1 = clots in an unusual location (such as the brain or abdomen) and a low platelet count with or without antibodies that activate platelets (anti-PF4 antibodies)

  • Tier 2 = clots found in common locations (such as the leg or lungs) and a low platelet count and anti-PF4 antibodies

  • Not classified = case does not meet the criteria for Tier 1 or Tier 2 (for example clots in common locations with low platelet count but no evidence of anti-PF4 antibodies).

Cases have most often occurred about 2 weeks after vaccination, although the time to onset (or diagnosis) has ranged from one to 100 days (Table 3).

Table 3: Time to onset, treatment and outcomes for TTS cases*

Time to onset/ diagnosis (days)

Median (range)

18 (1-100)

Treated in ICU

At any point

45

Currently

0

Outcome

Discharged

131

In hospital

12

Fatal

8

*Data is based on the most recent medical information available to the TGA

Other safety signals with Vaxzevria (AstraZeneca)

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Guillain-Barre Syndrome (GBS)

GBS is a rare immune disorder affecting the nerves and can result in pain, numbness, muscle weakness and difficulty walking. It has been associated with COVID-19 infection as well as other infectious diseases. Following rigorous investigations by the TGA and other international drug regulators, a clear link between GBS and Vaxzevria (AstraZeneca) has not been established. However as a precautionary measure, a warning statement about GBS has been added to the Product Information in response to rare cases following vaccination.

To 3 October 2021, the TGA has received 137 reports of suspected GBS occurring after vaccination with Vaxzevria (AstraZeneca). These cases will be considered as part of our ongoing monitoring of this safety signal. It is expected that some suspected cases may not be related to vaccination, as GBS can also be caused by other common causes of GBS, such as viral infections and some types of gastroenteritis. 

We encourage people to seek medical attention if they experience symptoms that could suggest GBS as early medical care can reduce severity and improve outcomes. Symptoms to look out for include weakness and paralysis in the hands or feet that can progress to the chest and face over a few days or weeks. These tend to affect both sides of the body.

Immune thrombocytopenia (ITP)

The TGA continues to monitor and investigate reports of suspected ITP, a type of thrombocytopenia or low platelet count. We will communicate the outcomes of this investigation, including any regulatory actions, when it is complete. 

To 3 October 2021, the TGA has received 81 reports of suspected ITP following vaccination. These patients had an extremely low platelet count, and signs of thrombocytopenia which may include unusual bruising, a nosebleed and/or blood blisters in the mouth. Their symptoms occurred in a timeframe that suggested they could be linked to vaccination and no other obvious cause was identified based on the information provided to TGA. Apart from one fatal case that was assessed by an expert Vaccine Safety Investigation Group as being likely to be vaccine related, suspected cases of ITP have not been definitively linked to vaccination.

ITP can occur when the immune system is activated, for example by a viral infection or vaccination, and mistakenly destroys platelets which help blood to clot. In many cases it is mild with up to a third of people having no symptoms at all, or only minor bruising. However, about 5% develop severe bleeding.

We encourage people to seek medical attention if they experience signs and symptoms that could suggest ITP, such as unusual skin bruising or clusters of small red or purple spots that do not lose their colour when pressed. Unusual bleeding is another sign, for example bleeding from the nose or mouth that is hard to stop, or blood in the urine or stools.

Up-to-date information about the expected side effects of Vaxzevria (AstraZeneca) can be found in the Consumer Medicine Information (for consumers) and Product Information (for health professionals).

Comirnaty (Pfizer) vaccine

To 3 October 2021, approximately 16.6 million doses of Comirnaty (Pfizer) have been administered in Australia. The reports of suspected side effects we receive for this vaccine are consistent with what has been observed in the clinical trials and by other medicine regulators overseas. Most side effects resolve within a few days.

The TGA is actively monit oring myocarditis (inflammation of the heart) and pericarditis (inflammation of the membrane around the heart) and continues to work with international regulators on this safety signal.

Up-to-date information about Comirnaty (Pfizer) can be found in the Consumer Medicine Information (for consumers) and Product Information (for health professionals).

Spikevax (Moderna) vaccine

The Spikevax (Moderna) vaccine is now being rolled out in Australia. To 3 October 2021, approximately 167,000 doses have been given. We have received 65 reports of suspected adverse events associated with the vaccine. These were expected reactions consistent with what has been reported in the trials and included injection-site reactions, nausea, headache, dizziness and chest pain.

Up-to-date information about the expected side effects of Spikevax (Moderna) can be found in the Consumer Medicine Information (for consumers) and Product Information (for health professionals).

Myocarditis and pericarditis with mRNA vaccines

Myocarditis and pericarditis are rare effects on the heart that typically occur within 10 days of vaccination with the mRNA vaccines Comirnaty (Pfizer) and Spikevax (Moderna). Cases are usually transient and resolve following treatment and rest.

Myocarditis is seen much more commonly in people who become infected with COVID-19 than in people who are vaccinated and the Australian Technical Advisory Group on Immunisation (ATAGI) continues to emphasise that the protective benefits of the mRNA vaccines far outweigh the rare risk of these side effects in all eligible age groups

We encourage people to seek medical attention if they experience symptoms that could suggest myocarditis or pericarditis. This includes chest pain, palpitations (irregular heartbeat), fainting or shortness of breath after receiving the vaccine, particularly if they occur within 1–5 days. 

Initial tests for those presenting with symptoms include ECG, troponin and chest X-ray. Brief guidance on the initial assessment of children and adolescents with symptoms has been published by the Paediatric Research in Emergency Departments International Collaborative (PREDICT) network

ATAGI advises that people who develop myocarditis or pericarditis attributed to their first dose of Comirnaty (Pfizer) should defer further doses of an mRNA COVID-19 vaccine and discuss this with their treating doctor. 

To 3 October 2021, we have received 218 reports of suspected myocarditis alone or in combination with pericarditis. In addition, we have received 629 reports of suspected pericarditis alone with Comirnaty (Pfizer). In the same period we have received 3 reports of suspected pericarditis alone with Spikevax (Moderna). 

These events can occur due to other causes, including common viral infections, so it is expected that not all cases are related to vaccination. Our ongoing analysis of Australian data with Comirnarty (Pfizer) indicates there is a higher-than-expected number of cases of myocarditis in vaccinated compared to unvaccinated individuals and that cases are more common in teenage boys after the second dose. This is similar to findings from other drug regulators overseas. Cases are usually short-lasting and resolve following treatment and rest.

Recently, Sweden and Denmark have temporarily paused the use of Spikevax (Moderna) for those aged under 31 and 18 years respectively, based on a study in progress carried out by Danish, Norwegian and Finnish public health agencies. The final report from this study is due in a month’s time. At this time, the European Medicines Agency approval of Spikevax (Moderna) for people over 12 years of age has not changed.

The Canadian province of Ontario has issued a recommendation that those aged 24 and under receive the Comirnaty (Pfizer) vaccine preferentially over the Spikevax (Moderna) vaccine. However, this is not a nationwide recommendation and the Canadian National Advisory Committee on Immunization ‘continues to recommend vaccination with either mRNA vaccine for people 12 years and over, given the proven benefits of the vaccines in preventing severe illness and death’.  

The TGA is aware of these actions and the studies in progress, and notes that the changes made to the vaccination programs in Sweden, Denmark and Ontario are based on a very cautious approach to observations from real-world use of the vaccine. The risk of myocarditis with both Spikevax (Moderna) and Comrinaty (Pfizer) remains very low. It will be important to determine whether the difference in the frequency of reporting between the two mRNA vaccines of suspected myocarditis and pericarditis adverse events in some countries is due to greater awareness, or if it reflects an elevated risk. There was much greater awareness of the association of the mRNA vaccines with myocarditis and pericarditis by the time the Spikevax (Moderna) vaccine became widely used because its regulatory approval and roll-out was some months after the Comirnaty (Pfizer) approval and roll-out in most countries.

We continue to closely monitor this risk, including working closely with international medicines regulators to share emerging safety information, and closely monitoring any reports in Australia.

We also continue to review cases against an internationally accepted case definition for myocarditis to classify how certain it is that these cases reflect myocarditis. More detailed information on our analysis will be published in next week’s report. 

For more information, see guidance on myocarditis and pericarditis developed by ATAGI and the Cardiac Society of Australia and New Zealand (CSANZ).